Telegraphic and wireless transmission system



March 31, 1 31- G. BOGGERO 1,799,083

TELEGRA HTC AND WIRELESS TRANSMTSSION SYSTEM Filed Sept. 12, 1929 6 Sheets-Sheet 1 March 31, 1931. G. BOGGERQ 1,799,083

TELEGRAPHIC AND WIRELESS TRANSMISSION SYSTEM Filed Sept. 12, 1923 6 Sheets-Sheet P 1931. G. BOGGERO TELEGRAPHIC AND WIRELESS TRANSMISSION SYSTEM March 31 Filed Sept. 12, 1929 6 Sheets-Sheet 3 March 31, 1931. e. BOGGERO 1,799,083

EGHA HTC [\ND WIRELESS TRANSMISSION SYSTEM TEL Filed Sept. 12. 1929 6 Sheets-Sheet 4 March 31, 1931.

G. BOGGERO Filed Sept. 12 1929 6 Sheets-Sheet 6 Fig. 8

t I v we M 159 Fig.7

Patented Mar. 31, 19 31 UNITED, STATES oIo'vANm BOGGERO, or Ttmin, ITALY, Assrenoa To 5. A. 3.1. a, BREVE'I'TI ITALIAN! EsTEaI, or Team, ITALY PATENT OFFICE socmTA An'om TELEGRAPHIC AND WIRELESS TaANsmssIoar sYsTm Application filed September 12, 1 929, Serial No. 392,167, and in Italy December 14, 1928.

This invention relates to telegraphic and wireless transmission systems, wherein groups of two or more variable frequencies are utilized for the formation of signal combinations said frequencies being produced by the depression of the keys of an ordinary typewriter keyboard and transmitted to the receiying station by any radiant energy such as Hertzian waves, carrier waves, electric currents and the like.

According to this invention each group of two or more variable frequencies representing a signal is obtained by means of an oscillating circuit comprising at least a thermionic tube, a constant inductance and two or more capacities generating'two or more frequencies, the combination of which represents the signal to be transmitted.

A characteristic feature of this invention consists in the fact that the frequencies of each group are transmitted in succession at a very short interval from one another and for this purpose a distributor. is provided which, when the key corresponding to the slgnal to be transmitted is depressed, will lead in due sequence the difl'erent capacities corres 0nding to the signal to be transmitted to t e 0s? cillating circuit.

A damper arranged on the distributor and a relay series will ensure the exact time connection and disconnection of said capacities.

To prevent any interference, it is necessary thatthe frequencies of each group be absolutely constant during transmission. This may be obtained by maintaining the inductance value constant and as the inductance is influenced by the variation of the field of the inductance winding due to unavoidable variation of the plate current, according to this invention, a secondary compensating inductance is wound on the main inductance through which the current flows inopposite direction, said compensating inductance being such as to automatically compensate the variation of the main inductance. Owing to this arrangement, the frequencies of each group are malntained perfectly distinct from one another.

According to another constructional form of this invention, the frequency variation by the depression of. the ke s or they may is obtained using variable 'in uctances in lieu of capacities. Said inductances may be connected in series and the combinations of frequencies representing the signals may be obtained by means of changers operated be connected in series for predetermined frequency values and in parallel for the intermediate values. For said intermediate values capacities may also be used instead of inductances in parallel.

The receiving station comprises broadly a receiving apparatus which may be of any resonators which are energized when the transmitting station sends off a predetermined signal which individualizes the receiving station, with which it is desired to communicate, close a circuit which starts the motor of the printing machine and closes'a' switch which prepares the circuits ofthe receiving set so that they will be-ready for the reception.

The printing machine comprises a combinator, by means of which the circuits controlling a relay are closed in the due sequence,

said relay operating a hammer acting on a type wheel in such a way as to print the symbol correspondingto the received signal on a sheet of paper placed on a carrier, an electromagnetic coupling moving the carrier through a spaclng, so that it will be ready to receive and print a new signal, and a relay to return the energized comblnating relays 1nto their initial position.

The combinator may be constituted by a disk carrying on its periphery insulated contacts, on which slide two insulated contacts carried by an insulating arm moving .synchronously with the type wheels in such a way as to close the signalling circuits in the desired order and sequence by means of con;

tacts electromagnetically operated by the resonators. The combinator could also be constituted by a rotating cylinder of conductive material coated with a sheet of insulating material having slots and holes distributed in the manner of a ladder in order to close the signalling circuits in the desired succession.

The printing machine comprises moreover arrangements to move the sheet forward and return the carrier to its initial position to begin the wrinting of a fresh line. These devices are automatically operated by means of circuits which are closed by the carrier during its travel.

The annexed drawing shows by way of example, some constructional forms of this invention.

Figs. 1 and 1A show diagrammatically the connections and the apparatus of the transmitting system;

Fig. 2 is an elevation partially sectioned of the distributor;

Fig. 3 shows diagrammatically the variable inductances in series, which may be substituted to the capacities of Fig. 1;

Fig. 4 is a diagram of the variable inductances in series and in parallel, and

Fig. 5 shows a variable inductance to be used in combination with the capacities.

Figs. 6 and 6A show diagrammatically the connections and apparatus of the, receiving system;

Fig. 7 is a cross section of the resonator group, and

Fig. 8 is a detail of the printing carrier.

Referring to Figs. 1 and 2, 1 denotes a thermionic tube, wherein a filament 2 is fed by a battery 3 by means of a circuit 4 comprising an adjustable ohmic resistance 5, a plate 6 being connected in series with a compensating inductance 7.

8 is the battery of the plate circuit; 911, 9b, 9c, 9d denote condensers adapted to generate successive pairs of frequencies constituting the signals and successively connected two by two in the oscillating circuit, as it will be more clearly set forth hereafter. 10 is a'main inductance wound on the same core 11 of the secondary compensating inductance 7 and connected between the grid circuit 12 and the positive pole of the battery 8. An ohmic resistance 13 is provided for controlling the value of the main inductance to the desired degree, said ohmic resistance 13 being connected at one end with the negative pole of the battery 3 and provided at its other end with a movable contact by means of which it is possible to control. the number of turns of the inductance connected to the resistance circuit.

The condensers 9a, 9b, 90, 9d are connected two by two and according to a predetermined sequence to the oscillating circuit by means of relays 14a, 14b, 14c, 14d respectively, which are energized by means of keys 15a, 15b corresponding to the s gnals to be transmitted by means of the distributor 16.

Said distributor (see particularly Fig. 2) comprises a bell shaped electromagnet 17 secured inside a case 18 carrying axially a shaft 19 rotatably mounted in suitable supports and provided at its upper part with a steeppitched thread 20, engaging a hub connected with an armature 21, which is prevented from rotating by notches in which guiding rods 22 secured to the electroinagnet are engaged. By this arrangement, when the electromagnet is energized, its armature is attracted and causes the shaft 19 to accomplish a turn in one direction, and when it is deenergized, a spring (not shown in the drawing for the sake of simplicity) returns the armature into its position of rest, causing the shaft to turn in the opposed direction.

The shaft 19 passes through a cover 23 of insulating materal and carries on its protruding portion a resilient arm 24.- on the free end of which is secured by means of screws 25 an electrically insulated spider of conductive material. The cross arms 26a and 26b of the spider carry at their ends contacts which cooperate with a sector of conductive material 27 and a pair of contacts 28a 28b (electrically insulated from the distributor body) respectively. In the position of rest (shown in Fig. 1) the contacts 26a and 261) are held raised from the cooperating contacts by the resilient arm. For carrying said contacts into their operating position or in other words to depress them when they are caused to rotate by the shaft 19, an arm 29 is provided which carries at its free end a cam 30 cooperating with the bevelled ends 31 of a guiding sector 32, in order to force the contacts 26a and 261) against the sector 27 and series of contacts 28a, 28?) respectively when the armature 21 is attracted by the electromagnet and to raise them when the armature is returned into its position of rest. For this purpose the cam and bevelled ends are shaped in such a way as to force the end of the arm 29 to slide on the lower surface of the guiding sector 32 during operation and to pass on the upper surface of said sector during their return stroke.

The energizing coil of the electromagnet 17 is connected with a feeding battery 33 by means of a circuit 34 including a switch comprising a. fixed contact adjustable by means of a screw 35 and a. spring contact 36 actuated by a lever 37, as it will be more clearly described hereafter.

The sector 27 is connected to the positive pole of the battery 33 by means of a conductor 38, while the two contacts 280;, 286 are connected by means of conductors 39a, 39?) respectively to a series of elastic contact "secure I bringing the spring contact 36 in. engagepieces 40a, 40a and 406, 407) having the form ofan inverted V. The contact pieces 40a, 40a cooperate with fixed contacts 41a, 41'a' electrically connected to one another and by means of a conductor 42a to one end of the energizing winding of the relay 14a.

The contact pieces 40]), 40'?) cooperate with fixed contacts 416,410 insulated from one another and connected by means of conductors 42b, 42c, 4203 to the energizing winding of the relays 14b, 14c, 14d respectively. The other ends of the energizing windings of the relays 14a; 14b; 14c; 14d

are connected by means of a common conductor 43 to the negative pole of the battery 33.

When a key, for instance the key 1511, is depressed the contacts 40a, 40?) are simultaneously forced towards the fixed contacts 41a, 416; the circuits for the coils of the relays 14a, 146 are thus prepared. By continuin the pressure on the key, a tooth 44,

d to its stem, strikes a lever '37 thus ment with the contact 35. Thereby the energizing circuit 34 of the electromagnet 17 is closed; said electromagnet on being energized, attracts its own armature 21 and causes the shaft 19 and therefore the spider to rotate; the contacts 26a and 26b of this latter are depressed owing to the engagement of the cam 30 on the lowr surface of 5 the guide 32. The windings of the relays 14a, 146 are thus successively brought into the circuit on the battery 33 and said windings, when energized, successively close the circuits on the condensers 9a, 9b, which successively translate the two frequencies representing the signal, to a carrier wave transmitting circuit through the transformer 45.

A damper in an oil bath (see Fi 2) is rovided in order to ensure a perfect y uni orm rotating movement of the spiderand the closure of the circuits at regular'intervals. Saidda'mper consists of a small blade wheel 46 rotata 1y mounted in a container 47 filledwith oil, coaxially mounted on the distributor bottom; the shaft 48 of the blade wheel extends into the case 18 of the distributor and is connected with the shaft 19 arranged on the same axis by means of a helicoidal spring 49.

A locking device comprising a shaft 50 having a slot 51 traversed by the tooth 44 is arranged in order to prevent the opening of the energizing circuit of the distributor electromagnet before the spider has accomplished its stroke. When the tooth 44 has moved under the shaft and has closed the energizing circuit of the electromagnet of the distributor, the shaft 50 is caused to rotate so that its solid portion will be brought on the path of the tooth 44. This rotation is effected by means of a relay 52 connected in and has been returned into its position of rest the circuit 34 is opened and the armature 53 is returned into its posit-ion of rest by the spring 56. a

The formation of the groups of frequencies constituting the symbols to be transmitted may be effected by placing variable inductances in the circuit of the main inductance 10, instead of using the capacities 9a; 9b; 9c; 9d.

Fig. 3 shows diagrammatically a group of variable inductances 57 (1, 57b, 57 c, 57 d Which may be advantageously used in the place of the capacities 9a, 9b, 9c, 9d Each one of said inductances is subdivided in sections abutting stationary contacts 58, on which slides a contact carried by a rotating arm 59. In the illustrated example each inductance is subdivided into ten sectipns and each rotating arm 59 carries an index 60 sliding along a scale 61 carrying the correspondlng number.

It will be easily understood-that by the above arrangement a nearly unlimited num- .ber of combinations of groups of two frequencies representin the signals to be transmitted will be 0 tained. Said groups are translated to the transmitting circuit by means of the distributor already described with reference to Figs. 1 and 2.

Fig. 4 shows a more compact arrangement, wherein an inductance 62 is connected 1n serles to the main inductance. Auxiliary I capacities, as shown in Fig. 1. In this case the capacities will be utilized to obtain the intermediate frequencies between the value of the frequencies corresponding to the taps of the inductance 65.

It will of course be seen that other combinations of inductances and capacities may be used for representing the symbols to be transmitted and also other mechanical or v electrical arrangements may be used to ob-,

tain the same timed variationsand transmissions of frequencies without departmg from the spirit of this invention. 0

. Referring to Fig. 6, the receiving station comprises a group of resonators 100 having as many resonating elements as there are vario-generators of frequence (9 in the illustrated example), a group of recombinating relays 101 to 101 each relay being energized by means of a circuit, the closure of which is controlled by the corresponding resonating element, a set of contacts 102 to 102 carried by an insulating bar, a recombinator 103 carrying a circular set of equidistant contacts 104 formed by four groups of nine contacts numbered I to IX and suitably distribut'ed in such a way as to obtain a continuous succession of contact pairs representing the signals to betran'smitted (36 in the illustrated example corresponding to the keyboard'keys ofthe transmitting group). The contacts bearing the same number are connected to each other and to the corresponding contacts 102 cooperating with the recombinating relays 101.

A rotating arm carrying two contact pieces 105 and 106 slides on the contacts of the recombinator; said contact pieces 105 and 106 are electrically separated by a distance equal to the distance between the contact 104; one of said contacts is connected to ground at 107 and the other is connected to a pair of polarized relays 108 operating a main switch 109 controlling a circuit actuating a printing carrier and an electromagnetic coupling for printing the received signal and then moving the carrier forward. The receiving station is called by means of a conventional calling signal, which in the illustrated example is represented by two frequencies, to which the elements 100 and 100 of the resonator will respond. When the transmittin station sends ofi" the frequency corresponding to the element 100 this latter is set into vibration and only when it reaches the full Width of movement, thereby closing a circuit extending from ground at 111, resistance 112, conductor 113, relay Winding 101 and conductor 114, to the negative pole of the battery. The relay 101 when energized forces its armature into engagement with the contact 100 and thus the calling circuit is prepared. The frequency arriving being in resonance with the element 100 this latter, as above described, will close the energizing circuit for the relay 101 which, on being energized, forces its own armature into engagement with the contact 102 thus completing the calling circuit, which includes an auxiliary calling battery 115 and extends from the positive pole of said battery through the conductor 116, contact 102 armature of the relay 101 conductor 117, armature of the relay 101 contact 102, conductor 118 to the winding of the calling relay 119 and conductor 120 to the negative pole of the battery 115.

The relay 119 when energized attracts its own armature 121, thus closing a circuit extending from earth at 122, through the motor 123, conductor 124, core of the relay 119; armature 121 and conductors 125 and 114 to the negative pole of the battery 110.

The motor 123 is started and gives a rotary movement to the arm 105106 of the recombinator, type wheel and loose member of the electromagnetic coupling. In order to keep the motor going even when the energiz ng circuit above described is open, the calling relay 119 is provided with a coil 126 which maintains the armature 121 in the attracted position. Said coil is connected in parallel with the motor on the energizing circuit above described.

The rotating arm 105106, when reaching the adjacent contacts I--IX of the disk of the recombinator 103, closes a recombinatory circuit extending from the ground contact 106 through a contact 104 conductor 127, contact 102 armature of the relay 101 con ductor 117, armature of the relay 101, contact 102, conductor 128, contacts 1'04 and 105, conductor 129, polarized relays 108, conductors 130 and 131, armature 132 and conductors 133. to the negative pole of the battery 110. On closure of the recombinatory circuit the polarized relays 108 are energized, and carry the spring contact 109 on the right against the core of the relay on the right side. A printing circuit is thereby closed extending from the negative pole of battery 110,

through the conductor 133, armature 132,

conductor 131, spring contact 109, core of the right relay 108, conductor 134' and coil of the printing relay 135 to ground at 136. The relay 135 when energized actuates a hammer which strikes the symbol of the type wheel 142 represented by the two frequencies acting on the resonators 100 and 100 said symbol having been brought under the hammer synchronously with the arm 105 or 106.

At the same time a circuit is closed in parallel with the circuit above described which energizes, through the conductor 127, the exciting coil of the electromagnetic coupling 138, which will thus be closed setting the threaded shaft 139 in rotation, which moves the printing carrier 140 forward, a ratchet wheel 141 being keyed on said shaft.

Finally a third circuit is closed through a relay 149 resetting the armatures of the recombinatory relays-100 100"; said resetting relay, attracting its'own armature 150 closes a circuit extending from ground at 151, through the armature 150, conductor 152, resetting coils 153 of the actuated recombinatory relays 100 and 100, conductors 154 and 114 to the negative pole of the battery 110. The armatures of the relays 1 01 and 101 are separated from the cooperating contacts 102 whereby the above described recombinatory circuit is opened.

The rotation of the ratchet wheel 141 raises the pawl 142 which passing from one tooth to another closes for the time being through the contact 143 a circuit extending from the negative pole of the battery 110 through the conductor 144, primary winding 145 of a transformer, conductor 146 and contact 143 to ground at 147. As soon as this circuit is opened, an electromotive force is generated in the secondary winding 148, said electromotive force energizes the polarized relay 108 on the left and disenergizes the one on the right carrying the spring contact 109 on the left into the position of rest.

The printing circuit is thus interrupted, the coupling is disenergized and disengaged thus stopping the forward movement of the carrier, the resettin relay 149 is disenergized and disengaging its armature 150 a circuit extending from ground 136, through H relay 157 the relay 163 is energize the contact 155, conductor 156, winding of a relay 157 locking the carrier, conductor 158, spring contact 159, conductors 160 and 114 to the negative pole of the battery 110. The relay 157 when energized attracts the arm 161 of the pawl 142, disengaging the ratchet wheel, so that the carrier is forced by the spring towards the left and causes the steep-pitched screw 139 to turn in a direction opposed to the forward direction. In order to maintain the pawl 142 raised during the movement of the carrier, the pawl is connected to ground and the core of the stop relay 157 is connected by means of the conductor 162 to the conductor 156, that is to one end of the energizing .winding of said relay; the above described circuit remains thus closedeven when the carrier is separated from the contact 155.

Simultaneously with the energizin of the E which attracting the armature 132 breaks the recombinatory circuit in order to prevent an accidental formation of the following combination during the return of the carrier. Moreover the relay 164 is energized for the forward movement of the paper and, by means of a lever 165 connected to its armature and a ratchet and pawl mechanism 166, causes the shaft 167 of the paper roller 168 to perform a rotation through a spacing. The relays 163 and 164 are connected in parallel to the relay 157, so that, when the carrier reaches the end of its stroke towards the left and meets the spring contact 159 it breaks the circuit of all said relays, which, on becoming disenergized set their armature free, said armatures returning into thein initialposition as shown in the drawing.

At the end of the message writing the motor 123 must be stopped in order to avoid a free run thereof. For this purpose a relay may be arranged to break the energizing circuit of the motor, said relay may be actu-- ated by the transmitting station automatically a certain time after the transmission is over. Means can also be provided to displace the paper through a distance corresponding to two or more spacings when the writing of the telegram is ended, in such a way as to separate a telegram from the following one.

What I claim is:

1. In a signalling system, the combination with a transmitting station, a receiving station, an oscillating circuit at the transmitting station comprising a plurality of ca acities which can be successively connecte to said oscillating circuit, a keyboard at the transmitting station to close said oscillating circuit and a printing apparatus at the receiving station, of means at the transmitting station to close in succession at each depression.

of a key the oscillating circuit through two of said capacities in order to superpose on a carrier wave of constant frequency two successive waves of differe tfrequencies representing the symbol of the depressed key, resonanting means at the receiving station tuned to said frequencies and means operated by the resonating means for preparing circuits operating the printing apparatus on the arrival of the first frequency and to complete said circuits on the arrival of the second frequency.

2. In a signalling system, the combination with a transmitting station, a receivin station, an oscillating circuit at the transmitting stationcomprising a plurality of capacities adapted to be successively connected to said oscillating circuit, a main inductance and a compensating inductance, a keyboard at the transmitting station to close said oscillating circuit and a printing a paratus at the receiving station, of a distri utor at the transmitting station to close, in succession at each depression of a key, the oscillating circuit through two predetermined capacities in such a way as to superpose on a carrier wave of constant frequency two successive waves of different frequencies representing the symbol of the depressed key, resonators at the receiving station tuned to said frequencies and means operated by the resonators for preparing actuating circuits of the rinting apparatus on arrival of the first f requency and to complete said circuits on arrival of the second frequency.

3. In a signalling system, the combination with a transmitting station, a receiving station, an oscillating circuit at the transmitting station comprising a plurality. of capacities adapted to be successivel connected to said oscillating circuit, a key card at the transmitting station to close said oscillating circuit and a printing apparatus at the receiving station, of a distributor at the transmitting station comprising a bell-shaped electromagnet energized by the depression of any key, an armature, a shaft having a steep-pitched thread on which said armature is fitted, means to prevent said armature from rotating, a spider having movable contact pieces carried by an elastic arm keyed on said shaft, stationary contact pieces, means to bring said movable contact pieces in engagement with said stationary contacts during the operative stroke when said electromagnet is energized and to disengage said movable contact pieces from the stationary contacts during the return stroke when said electromagnet is deenergized, of a plurality of relays, each one of said relays being adapted to close the oscillating circuit on one of said capacities, said relays being included in a circuit comprising a source of energy, said distributor and a set of switches actuated two by two each key of the keyboard in such a way as to connect to said circuit in succession two of said relays each time a key is depressed to close in succession the oscillating circuit on two corresponding capacities, thus superposing on a carrier wave of constant frequency two successive waves of different frequencies, resonators at the receiving station tuned to the frequencies of the oscillating circuit and means actuated by the resonators for preparing the circuits operating the printing apparatus on arrival of the first frequency and completing said circuits on arrival of the second frequency.

4. In a signalling station, as claimed in claim 3, a blade damper for the distributor connected by elastic means to the shaft having a steep-pitched thread.

5. In a signalling system, the combination with a transmitting station, a receiving station, an oscillating circuit at the transmitting station comprising a plurality of capacities adapted to be connected in succession to said oscillatingcircuit, a keyboard at the transmitting station to close said oscillating circuit and a printing apparatus at the receiving station, of a plurality of relays corresponding in number to said capacities for 1ncluding in succession said capacities in said oscillating circuit, an energizing circuit for said relays comprising switches actuated two by two by the keys and a distributor to close in succession said energizing circuit on two of said relays corresponding to the symbol of the depressed key, in such a way as to transmit two waves of different frequencies on a carrier wave of constant frequency, an operating electromagnetfor said distributor, a circuit for said electromagnet, a switch in said circuit, a tooth carried by each key to close said circuit when said key is depressed, a device for locking said key in the depressed position until completion of the distributor operation, resonators at the receiving station tuned to said frequencies and means operated by said resonators for preparing actuating circuits of the printing apparatus on arrival of the first frequency and completing said circuits on arrival of the second frequency.

6. In a signalling system, as claimed in claim 5, a key locking device comprising a latch and a relay acting on said latch and included in the energizing circuit of the electromagnet of the distributor.

7. In a signalling system, the combination with a transmitting station, a receiving station, an oscillating circuit at the transmitting station comprising a plurality of capacities adapted to be connected in succession to said oscillating circuit, .a keyboard at the trans mitting station to close said oscillating circuit and a printing apparatus at the receiving station, of means at the transmitting station to close in succession on each depression of a key the oscillating circuit through two of said capacities in such a way as to superpose on a carrier wave of constant frequency two successive waves of different frequencies representing the symbol of the de pressed key, a group of resonators at the receiving station having a number of resonat ing elements equal to the number of said capacities, a group of combinatory relays, an energizing circuit for said relays, the clo sure of which is controlled by the resonating element brought to oscillate on arrival of the corresponding frequency and a recombinator closing the circuits controlling the printing apparatus.

8. In a signalling system the combination with a transmitting station, a receiving station, an oscillating circuit at the transmitting station comprising a plurality of capacities adapted to be connected in succession to said oscillating circuit, a keyboard at the transmitting station to close said oscillating circuit and a printing apparatus at the receiving station, of means at the transmitting station to close in succession, on each depression of a key the oscillating circuit through two of said capacities in such a" way as to superpose on a carrier wave of constant frequency two successive waves of different frequencies representing the symbol of the depressed key, a group of resonators at the receiving station having a number of resonating elements equal to the number of said capacities, a group of combinating relays, an energizing circuit for said relays, the closure of which is controlled by the resonating element brought to oscillate on arrival of the corresponding frequency, a recombinator constituted by a disk carrying a circular set of fixed contacts numbered according to a predetermined order to form the combinations constituting the symbols, the contacts bearing the same numbers. being electrically connected to each other and to the contact of the corresponding recombinatory relay, a'rotating arm carrying. two insulated contacts cooperating with said set of 'fixed contacts,

a source of energy, one pole of which is connected to one of said movable contacts, a pair of polarized relays connected 1n series to the other pole of said source of energy and to the other movable contact, a control bol of the depressed key, a receiving station comprising a source of energy, a motor,, a printing apparatus constituted by a stepwise advancing carrier, a type wheel fitted in said carrier and receiving a uniform movement from said motor, an electromagnetic coupling through which the stepwise forward move-- ment of the printing carrier is efi'ected, a pr nting electromagnet, an energizing circuit for said electromagnet, a recombinator comprising a circular series of fixed contacts and an arm having two insulated contacts and receiving from said motor a rotating movement in synchronism with the type wheel motion, said recombinator being placed in the control circuit of the printing apparatus, a group of resonators having a number of resonating elements equal to the number of capacities, a'group of recombinatory relays, an energizing circuit for said relays, the closure of which is controlled by the resonatmg elements thrown into operation, on arrival of the corresponding frequencies, said relays controlling the notor circuit and preparing the controlling circuit ofthe printing electromagnet and electromagnetic coupling, said circuit being completed when the recombinator arm slides on the fixed contacts corresponding to the received symbol.

10. In a signalling system, in combination, a transmitting station comprising an oscillating circuit having a number of capacities adapted to be successively connected to said oscillating circuit, a keyboard and means for closing successively, each time a key is depressed, the oscillating circuit through two of said capacities in such a way as to superpose on a carrier,wave of constant frequency two successive waves of difierent frequencies representing the symbol of the depressed key, a receiving station comprising a source of energy, a motor, a stepwise advancing carrier carrylng a type wheel receiving a. uniform motion from said motor, an electromagnetic coupling, through which the stepwise forward movement of said carrier is effected, a printing electromagnet, an energizing circuit for said electromagnet, a recombinator comprising a circular set of fixed contacts and an arm having two insulated contacts and receiving from said motor a rotary movement in synchronism with the type wheel motion, said combinator being included in the controlling circuit of the printing apparatus, a group of resonators having a number of resonating elementsequal to the number of said capacities, a group of recombinatory relays, the energizing circuit of which is controlled by said resonating elements which are thrown into operation on arrival of the corresponding frequencies, said relayscontrolling the energizing circuit of said motor and preparing the energizing circuit of the printlng electromagnet said circuit being completed when the recom inator arm slides on the fixed contacts corresponding to the received symbol; a main switch included in the energizing circuit of the printing electro- -'magnet and electromagnetic coupling, a pair of polarized relays controlling "said switch, :1 circuit comprising said relays and a transformer and a switch operated by means of a pawl and ratchet device to generate in said transformer a current capable of actuating said polarized relays in such a way as to open said main switch when the printing of the received symbol has been completed.

11. In a signalling system, in combination, a transmitting station comprising an oscillating circuit having a number of capacities adapted to be successively connected to said oscillating circuit, a keyboard and means for a closing successively,each time a key isdepressed, the oscillating circuit through two of said capacities in such a way as to superpose on a carrier wave of constant frequency two successive waves of different frequencies representing the symbol of the depressed key, a receiving station comprising a source of energy, a motor, a stepwise advancing carrier carrying a type wheel receiving a uniform motion fromsaid motor, an electromagnetic coupling, through which the stepwise forward movement of said carrier is efl'ected, a prmtmg electromagnet, an energizing circuit for said electromagnet, a recombinator' comprising a circular set of fixed contacts and an arm having two insulated contacts and receiving from said motor a rotary movement in synchronism with the type wheel motion,

trolling circuit of the printing apparatus, a

.group of resonators having a number of v lays, the energizing circuit of which is consaid combinator being included in the controlled by said resonating elements which are thrown into operation on arrival of the cor responding frequencies, said relays controlling the energizing circuit of said motor and preparing the energizing circuit of the printing electromagnet, said circuit being completed when the-recombinator arm slides on the fixed contacts corresponding to the received symbol, a main switch included in the energizing circuit of the printing electromagnet and electromagnetic coupling, a pair of polarized relays controlling said switch, a circuit comprising said relays and a transformer and a switch operated by means of a pawl and ratchet device to generate in said transformer (a current capable. of actuating said polarized relays in such a way as to open said main switch when the printing of the received symbol has been completed and means for breaking the energizing circuits of the printing electromagnet and electromagnetic coupling when the carrier is at the end of its stroke.

12. In a signalling system, in combination, a transmittin station comprising an oscillating circuit liaving a number of capacities adapted to be successively connected to said oscillating circuit, a keyboard and means for closing successively, each time a key is depressed, the oscillating circuit through two of said capacities in such a way as to superpose on a carrier wave of constant frequency two successive waves of different frequencies representing the symbol of the depressed key, a receiving station comprising a source of energy, a motor, a stepwise advancing carrier carrying a type wheel receiving a uniform motion from said motor, an electromagnetic coupling, through which the stepwise forward movement of said carrier is efi'ected, a printing electromagnet, an energizing circuit for said electromagnet, a recombinator comprising a circular set of fixed contacts and an arm having two insulated contacts and receiving from said motor a rotary movement in synchronism with the type wheel motion, said combinator being included in the controlling circuit of the printing apparatus, a group of resonators having a number of resonating elements equal to the number of said capacities, a group of recombinatory relays, the energizing circuit of which is controlled by said resonating elements which are thrown into operation on arrival of the correspondlng frequencies, said relays controlling the energizing circuit of said motor and preparing the energizing circuit of the printing electromagnet, said circuit being completed when the recombinator arm slides on the fixed contacts corresponding to the received symbol, a main switch included in the energizing circuit of the printing electro magnet and electromagnetic coupling, a pair of polarized relays controlling said switch, a circuit comprising said relays, a transformer and a switch operated by means of a pawl and ratchet device to generate in said transformer a current capable of actuating said polarized relays in such a way as to open said main switch when the printing of the received symbol has been completed, and means for breaking the energizing circuits of the printing electromagnet and electromagnetic coupling when the carrier is at the end of its stroke, means for the forward movement of the paper on which the printing is efi'ected, and means for breaking the recombinatory circuit for the purpose of preventing that during the movement of the carrier the printing device be influenced by the arrival of a successive signal.

In testimony that I claim the foregoing as my invention, I have signed my name.

GIOVANNI BOGGERO. 

